Omega
by LadyAiki
Summary: After looking up the Mario Brothers past history Luigi finds out he is the last of the remaining Omegas in recorded history. Omega and Alpha AU featuring Uke Luigi. I don't own the Mario Characters.
1. Chapter 1

It was late into the night for the citizens of the Mushroom Kingdom everyone was sound asleep in their beds. Princess Peach however was wide awake as she scanned through some ancient documents from her family history that were hidden within the archives of the castles library.

Peach sighed rubbing her temples in frustration before hearing her bedroom door open slowly revealing her guardian Toadsworth.

"My dear why are you up so late?" He asked giving the papers in her hands a casual glance.

"Um it's nothing Toadsworth just wanted to look into something that was bugging me for some time?" She laughed softly before yawning.

"Well maybe we can look into later after you get some proper rest?" Toadsworth smiled gently.

"Alright goodnight"

After the elder toad left Peach was sure to lock the door tightly.

"Alright let's figure this out…"

It was into the next morning Peach fell asleep with her arms on the desk and the papers scattered all around.

A sudden knock on the door alerted the Princess to jolt awake with a squeal of shock.

"Princess is everything alright the door is locked…" Peach sighed rubbing her head.

"Sorry it's a habit you know…" She heard the familiar hum of acknowledgement from the elder toad.

"Of course Princess, but that is not why I am here there seems to be a great disturbance"

Peach's eyes widened in alarm already getting dressed for the day," What is the problem have you contacted Mario and his brother?"

Toadsworth grew silent for a moment before her spoke another word.

"Ah..that's the problem Princess it was Master Mario who called his little brother Luigi fell ill with a very high fever this early morning" Toadsworth face looked grim for the younger Mario brother's condition.

Peach's eyes widened in shock before reaching for her papers," Um tell Mario I'll be there momentarily"

"I understand Princess.."

After reaching the Mushroom Kingdom Hospital there she spotted the hero himself sound asleep.

Peach cleared her throat softly," Mario it's me…" Mario jolted awake turning his head to Peach his blue eyes wide.

"Princess oh thank goodness" He sighed looking rather upset.

"How long has Luigi been here?" Peach asked taking her seat next to the elder brother who grimaced.

"The staff took him into the emergency hoping to contain his fever they said it's not as bad as it was, but they are worried about how it got like that out of the blue…" Mario sighing with shaky breath.

Peach smiled softly before showing Mario her findings," Mario there might be a reason for all of this?"

"Oh really?" Mario glanced up to his best friend his eyes full of hope.

"Yes in fact I was up pretty much all night looking into my family roots that tie back ten of thousands of years ago" Mario felt his throat clench.

Peach smiled," I even took a glance into your history" Mario frowned slightly.

"What does that have to do with Luigi…"

Peach chuckled," Simple have you heard of the omegas?"

"Excuse me?"

To put it simply those fevers that Luigi is going through is simply him going through a phase of sorts"

"A phase is that it?"

"That depends of how you look at it Mario" The Princess sighed rubbing her head gently.

"What aren't you telling me Peach is Luigi going to be alright or not?"

"Yes, but we shouldn't talk here come to my castle in a few hours and we can discuss more"

"B-But what's so bad about not speaking about it here?" Mario asked.

"Its supposed to be a hidden secret I'm really not supposed to be telling you any of this, but all more I can say is Luigi will be fine he's not in danger at the moment"

"Wait at the moment what does that mean Peach?" Mario's eyes narrowed in concern for his brothers safety.

Before he could get any more answers the nurse had called for his presence. Mario sighed shaking his head before stalking off to his little brothers room.

Peach smiled softly before she followed behind Mario to see Luigi.

* * *

A/N: Yes you heard right girls and boys this is going to be a Omega and Alpha AU with Luigi as Uke. For all those who wanted Mario as the submissive I'm sorry I won't ever write Mario as some bottom. This has Waluigi, Bowser, Wario, King Boo, Mr. L, Dimentio and Mario with our darling cutie so if anything like this upsets you please be respectful and hit the back button. This is my first Yaoi story for Mario so if you have any 'Great' Criticism that would be helpful for my future writing then by all means go for it. But people please don't flame and say 'eww yaoi so gross why won't you write Hetero or die' Trust me I've heard better out of a five year old and that five year old threatened me with a gun. So thank you and have a nice day my lovely viewers.


	2. Chapter 2

Omega

Blurry eyes slowly opened to be greeted by two familiar faces both looking rather worried.

"How are you feeling little brother?" The younger brother turned his head to see Mario smiling gently at Luigi who sighed.

"Honestly I feel like crap Mario..." Peach bit her lips nervously something that didn't go unnoticed by Mario.

"Look it's probably nothing bro I probably ate something that was rotten.." Luigi laughed gently trying to put everyone at ease.

Mario opened his mouth to respond, but the door opened up showing the doctor and two nurses by his side.

"How are you feeling today Master Luigi?" The younger brother sighed.

"I don't know whats wrong with me sir honestly one minute I was reading at home then I had this horrid burning sensation then nothing…."

Mario whipped his head to Peach whose face was frowning.

"Peach…?"

"Doctor is Luigi going to be alright?" Peach asked quietly

"Yes it seems whatever has overcome the lad has passed for the moment" Peach sighed with relief but the elder brother seemed less then assured.

"Good..."

"But I need to have a word with the both of you for a moment outside" He gave then both a pointed look.

"Alright" Peach and Mario both bid Luigi farewell quickly walking out the door.

"Princess Peach something isn't right this heat that Master Luigi was overcome with wasn't normal" The doctor muttered.

Peach breathed in and out trying to steal her nerves.

"Peach what is going on is Luigi alright?" Mario's blue eyes narrowed at the thought that Luigi's life was in danger.

"Look Mario he's not dying if that is what you are worried about" Peach mumbled.

"Then what is going on?" Mario hissed hating being out of the loop.

"Master Mario do you know of the Alphas and the Omegas?" The doctors voice now took on a sharpened tone as he stared deep into the elder brother's blue eyes.

"Alphas and Omegas what?" Poor Mario was truly confused.

"Oh my apologies this was before your time..."

"Excuse me?"

"You might want to sit down Mario this is going to be a long explanation" Peach whispered to the hero as he grumbled under his breath.

"This is was before Princess Peach's timeline way before you come across the Mushroom Kingdom and before she become who we all know and love"

"Anyways during the Queen and King's rule of the Mushroom Kingdom there was a strange development going around many civilians were undergoing heats unseen by many"

"Though very similar they were acting very differently for different purposes and strangely enough they only effected the male population" The doctor smirked slightly.

"So why is Luigi only effected how come I am not?" Peach sighed folding her arms across her chest.

"Mario I did some digging into your family history and found something really interesting" Peach whispered.

"What did you find out?"

"Turns out your father's side has genes remotely similar to the Omegas in this timeline which of course passed on to Luigi"

"What does that mean how come I wasn't hit?"

The doctor sighed," Mario this may be hard for you, but due to Luigi's shy personality and now cooping with the ongoing loneliness that only which now fueled the Omega Gene to where his heat is now starting to take its full effects"

"Oh God are you telling me that this is my fault Luigi is like this?"

"Of course not however it was bound to happen due to Luigi's longing for companionship" The doctor assured the elder plumber, but now Mario was standing up right in the doctor's face his face full of rage.

"Don't fret Master Mario it's nothing bad I assure you sure he will be receiving copious amounts of attention from every possible Alpha Male wanting to form a relationship with him, but-"

The doctor's neck was snatched by an overprotective elder brother whose eyes now glimmered with unrelenting hatred.

"What the fuck did you say"

"Mario think about he can finally get someone who loves him for him" Peach whispered her eyes gazing at her best friend with despair.

"Peach have you lost your mind my little brother is now considered a walking target" Mario slumped to the ground his mood now soured.

"Mario calm down this is difficult for me too I never dreamed he would be an Omega, but you need to be excepting of this whether you like it or not" Peach's eyes darkened slightly her posture standing firm.

Mario snorted before leaving the room slamming the door behind him.

"Have I made an error Doctor?" Peach whispered her eyes looking at the door with a saddened look.

"Not in the slightest, but if the books are true then Luigi might attract potential enemies as well so we need to keep our eyes alert" Peach nodded before taking her leave bidding the doctor a goodnight.

Outside within the halls Mario was storming back to his brother's bedside, but Peach stopped him.

"Mario listen to me think about what is best for Luigi what about his happiness" Peach reached for the other, but he shrugged it off.

"Don't start Peach I won't allow my brother to be taken advantage of by other men" Mario hissed his hands already on the knob.

"Mario are we sure this isn't about you we are talking about?"

"Excuse me?" He turned around to fully to face her.

"For years you ignored him and treated him like a common pest now all of a sudden he would be finally getting attention he desperately wanted yet you cannot accept it figure that out?" Peach hissed her blue eyes glared back at the other.

"Say what you want Princess, but Luigi is the only family I have left Good Night Princess" Mario slammed the door shut cutting off her words.

"Dammit it Mario..." She slammed her fists against the wall before letting out angry huffs of air she stormed back to her castle.

* * *

A/N: Yes everyone I did write this exactly how I intended. Mario is very much a jerk towards Luigi believe what you want. I always pictured Luigi wanting to be like his Big Bro wanting to help him, but being pushed away by him this is what led to his Omega Genes fully developing. The Alphas will be picking up on his desires for companionship and will soon advance.

I have put a poll on my profile with potential pairings that will be in this story. There is no Daisy or Rosalina with Luigi otherwise it defeats the purpose of a Yaoi Story. I won't listen to any nasty or negative flames that people write. Honestly this is a Fanfiction Yaoi Story why do people complain if it's supposed to be fictional not real? I write for my creatively and wanting to get better, but if people want to continue to write flames and hateful comments then maybe they should go look elsewhere.

Anyways I don't own any of the Characters otherwise I would get rid of all Mary-sue Characters. Thank you for all those who have reviewed and commented on my profile I hope everyone has a nice day.


	3. Conversations

Omega

The next few days came and went as Mario tended to his little brother whose fever climbed to dangerous high levels.

Graduating from the very best medical school back in their home town was well worth the time spent if he could help Luigi.

Mario sighed softly as he dunk the wet rag back into ice cool water before gently pressing it against Luigi's sweating forehead.

"Oh Luigi I wish I could help more..." Mario mumbled as he sipped some water before turning his head looking out the window.

"Mario can I speak with you for a moment?" Mario glanced over to see that Toadsworth was standing by the doorway a frown etched upon his features.

"Sure"

Both Mario and Toadsworth walked out into Luigi's private gardens both Mario and Toadsworth looked around in awe at the beauty and wonder.

"Did Luigi do all of this?" Toadsworth gaped in shock his eyes taking in the scenery.

"Yep since I wasn't taking him on adventures much he decided to grow a green thumb and turn this place where he could enjoy himself" He mumbled offhandedly.

Toadsworth hummed in thought," I suppose I should tell you the real reason I am here"

Mario sighed rubbing his forehead," I think I have a guess"

"Yes it's quite unfortunate that young Luigi is the Omega"

"Is it that bad Luigi is an Omega I mean-"

"Master Mario you must understand this is serious Luigi might not be ready for someone surely you know this"

"Luigi is well in his early twenties I'm sure he's fine-"

"Mario let me rephrase this Luigi is at risk for any potential male to bring harm to him"

"Excuse me?"

"Think about it for a moment Luigi being an Omega would bring about devious males wanting to take advantage"

"Isn't that the point for him to have a relationship?"

"That's true, but what it were Bowser or King Boo clearly they hold grudges upon both of you and won't be afraid to destroy any kind of innocence Luigi has left"

Mario blanked out as the words said numbed his mind," Oh god"

"I'm not saying this couldn't turn out with good intentions, but with Luigi's risk of always getting into trouble that poses greater chances of him being abused"

Mario bit his lips so much they bled.

"Just talk to him and help him along this process and maybe this will turn out alright?"

"Alright"

"Good night Master Mario"

Luigi looked up from his book to see his elder brother having a very dismal look etched on his face.

"Big Brother is everything alright?" Luigi asked worry clearly evident on his face.

"Oh you're awake how are you feeling?"

Luigi smiled cheerfully," I feel alright I just woke up"

Mario smiled gently at his little brother before hugging him tightly," Mario?"

"Luigi we need to talk"

"Sure"

A Few minutes later Mario and Luigi found themselves on the loveseat of their house.

"So what did you want to talk about?"

Mario rubbed the back of his neck," Uh I don't know how to say this other than do you know why you're body was out of whack?"

Luigi frowned tilting his head to the side," Not a clue I felt strange since this happened my body has these feelings" The younger brother felt his cheeks flush," Uh you know the sexual kinds"

Mario closed his eyes nodding," I know that's why I need to talk you something important and please don't freak out"

"Mario?"

"The real reason you're feeling this way is because our family has what is called Omega Genes"

"Omega what now?"

"Omegas they are sought after as treasured mating partners for dominate males" Luigi gaped his mouth wide and ajar.

"M-Mating partners" Luigi was now a blushing mess.

"Yes Luigi you are the last of the Omegas" Mario said hollowly.

* * *

A/N: There you have it people Mario told Luigi the truth, but how will Luigi take this news? The voting is done and the winner is Mr. L will be the first at wooing Luigi.

No Mr. L and Luigi are totally different peoples. Mr. L is a suave flirty asshole while Luigi is shy and naïve when it comes to romance. Again I am stating that Daisy will not be one of the characters involved with Luigi because it defeats the purpose of this story. So if that upsets you or you're hetero fantards then don't read this story please.

To everyone who reviewed, favorited and or following thank you so much that brings me great happiness knowing that my story is doing ok.


	4. It's Mr L's Time

Omega

Luigi sat there stunned beyond words at what his older brother told him.

"W-what?" Luigi stammered nervously his blue eyes wide in disbelief.

"I'm serious Luigi you're what you call an Omega a species that are very rare in this world" Mario whispered now taking a spot next his little brother his lips quirked in a sad smile.

"B-but I've never heard of such a thing Mario how is this possible?" Luigi muttered.

"To be honest neither have I, but Peach must have dug into some family history and somehow within our family tree there have been records of Omegas"

"..."

Luigi found himself embraced in a gentle hug," It's going to be alright Luigi we're going to figure this crap out" Mario was quick to assure the younger brother.

The phone ringing startled the brothers from their conversation.

"Oh that must be Peach right now.." Mario tilted his head before quickly reaching for his phone.

"Yes Peach?"

"Mario good to finally hear from you how is Luigi?" Peach whispered gently hoping she wasn't disturbing the younger plumber.

"Oh trust me Peach Luigi is wide awake he woke up sometime after you left the hospital"

Mario could hear the sigh from the other side," I see I take it you told him?"

"Luigi was questioning why his fever was so bad it needed to be said"

"I agree Mario anyways come to the castle right away Toadsworth needs to speak with him"

"Alright we will be there soon Peach"

"Be safe Mario…"

Turning to his little brother who was beyond confused now stared at Mario in question.

"Was that Peach what did she need?"

"We need to head to the castle little brother she has more information for us about your status as an Omega"

"Oh alright big brother" Luigi smiled.

" _ **You guys know the plan correct?"**_

" _ **Yes my Lord…"**_

" _ **Good then move out quickly so when those pathetic plumbers arrive we can give them the perfect welcome**_

" _ **Yes Sir"**_

Once the Mushroom Kingdom came into view Mario instantly spotted Princess Peach and Toadsworth by his side.

"Peach good to see you…"

Peach smiled to her heroes before giving them a friendly hug.

"Mario, Luigi it's good to see you again I'm glad you arrived here safely…"

Toadsworth looked around nervously," You both weren't followed correct?"

"I'm not sure at the moment I wanted to make sure Luigi was safe"

"Fair enough now quickly come inside there is much to discuss…"

With both brothers inside Toadsworth locked the door behind him.

"Now Young Luigi there is much to tell you about what you are going through at the moment…"

"Can you tell me from the beginning maybe about why me…" Luigi closed his eyes bitterly.

"Luigi maybe this could be a positive?"

"H-how?"

"Well let's tell you about what an Omega is…" Toadsworth reached for a giant book.

"Ah here it is now according to this an Omega is a submissive male in an same sex relationship"

"!?" Luigi's cheeks flared bright red at the mere implications of anything sexual.

"Toadsworth I think you might have broke him…" Peach whispered softly.

"Nonsense he is a strong lad and if he is to prepare for what he is getting involved with he must know every detail this entails" Luigi whimpered covering his face with his hands.

"Toadsworth let take a break my brother needs a rest to let this soak in?"

"Ah I suppose let's resume in a good ten minutes…"

"Thank you Mario…" Luigi smiled brightly

"You're very welcome little brother" Mario smiled gently brushing the fringes from the others face.

Luigi blushed shyly turning his head to the side.

"Hello plumbers"

Mario gasped only to be shoved to the side and knocked unconscious by Koopa Troopas.

Luigi gasped in fright," Mario!" His blue eyes turning face the attackers who had now surrounded him.

"Now don't make this difficult little one we don't have to do this the hard way?" The lead Koopa Troopa smirked at the younger brother.

Luigi edged backwards seeing the Koopas walking towards him.

"We don't bite much.."

Luigi remained frozen as the Koopas waited for his answer.

"Let's get him boys…"

Luigi squeaked in fright ducking as two koopas dove for him.

"You can't hide and duck forever little Luigi sooner or later we are going to catch you"

"Leave me alone!"

The leader koopa troopa spun quickly attacking Luigi in the side causing him to stumble.

Luigi grimaced in pain," Ngh…" Blood seeping from his outfit.

"Let's wrap this up boys!"

All three Koopa Troopa spun towards the injured plumber who was gasping for air.

Luigi closed his eyes waiting for the oncoming pain only to head the crackling of lightning and loud explosion.

Luigi opened his eyes to see a shocking figure standing in front of him," W-who are you?"

The mysterious male turning his head slightly Luigi noticing just the faintest of silver in his eyes.

'He's handsome…" Luigi felt his cheeks heat up.

"Who the hell you think you are punk!" The leader Koopa Troopa hissed at the mysterious male who turned his attention directly towards him.

"It's my nature to defeat losers like you and to protect those I care about"

The male then step on the Koopa's shell earning a gasp of pain," Now I want you to do me a favor..." He smirked wickedly.

"If you attack him again you're going to regret it" With that warning in mind the Koopa Troopas quickly bolted out of there fearing for their lives.

Luigi gapped in shock at his savior," T-thank you so much…" Blue eyes stared at Silver.

The male smiled," You're very welcome"

* * *

A/N: Guess what time it is everyone! Mr L's time to show his stuff. Yes if you guessed it correctly the Koopa Troopas were sent by Bowser. For those who voted for Mr.L and Luigi together you're in luck there is going to be a good ton of them in chapters. I hope you enjoy this story so far. Read, Review and Enjoy.


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